1. Field of the Invention
This invention relates to a weighing unit for the cyclical and automatic weighing of bulk material, more particularly, tobacco, in which the charging and discharging operations occur practically without vibrating the sensitive measuring system of the scale.
2. Prior Art
Where cyclic weighing is carried out at a high speed, a problem arises of absorbing mechanical shocks in the system and the need of rendering them ineffective such that the weighing can be accomplished accurately and continuously. It is the purpose of this invention to isolate these vibrations (for example, the vibrations occurring upon the unloading of a weighing hopper having a flap or similar mechanism) and to prevent them from affecting the sensitive measuring component of a scale (for instance, an electro-dynamic scale). This is necessary in order to prevent premature wear and, therefore, weighing inaccuracies in the scale's measuring system.
Various ways of overcoming the problem have been attempted and form the prior art. For instance, it has been proposed that the complete weighing unit be resiliently suspended and damped, thus absorbing and, as well, reducing the loading and unloading shocks. Alternatively, it is also known to lock the weighing container during the loading and unloading phases in order to protect the measuring unit from shock. However, these arrangements afford only limited protection for the sensitive measuring parts of a scale.